Hourly cost of a $9000 ZTR mower ?

Have any of you figured the cost of operating a new $9000 ZTR mower? Depreciation, fuel, oil, filters, blades, belts, other parts replacement, are all expenses. I'm guessing at least $20 per hour cost just for the machine, not counting labor to operate it. Is this close, or am I way off?

Ok, if it costs less than $20 per hour, that's good! What's your estimate? I'm talking about a 72" with at least a 30 hp gas engine. If someone's post is correct about the 32 hp Generac using 2.75 gal per hour, that's real close to $6 per hour just for gas at today's price. If you depreciate it out for 3000 hours, that's $3 per hour just to own it. There is $9 per hour in those 2 costs alone. What do you figure?